ssl: remove OpenSSL::X509::V_FLAG_CRL_CHECK_ALL from the default store

With OpenSSL 3.6.0, it causes nearly every certificate verification to
fail with the message "certificate verify failed (unable to get
certificate CRL)" because the CRLs are typically unavailable in the
default store used by OpenSSL::SSL::SSLContext#set_params.

OpenSSL::X509::V_FLAG_CRL_CHECK_ALL is a flag that extends the CRL
checking to all certificates in the chain. In OpenSSL < 3.6.0, the flag
alone has no effect, and OpenSSL::X509::V_FLAG_CRL_CHECK must also be
set to enable CRL checking.

In OpenSSL 3.6.0, OpenSSL::X509::V_FLAG_CRL_CHECK_ALL now implies
OpenSSL::X509::V_FLAG_CRL_CHECK. This is inconsistent with the man page
and may be fixed in a future OpenSSL 3.6.x release, but this flag is not
needed and should not be set by default.

Fixes #949

Author: rhenium

lib/openssl/ssl.rb

@@ -92,7 +92,6 @@ class SSLContext
 
       DEFAULT_CERT_STORE = OpenSSL::X509::Store.new # :nodoc:
       DEFAULT_CERT_STORE.set_default_paths
-      DEFAULT_CERT_STORE.flags = OpenSSL::X509::V_FLAG_CRL_CHECK_ALL
 
       # A callback invoked when DH parameters are required for ephemeral DH key
       # exchange.